Smith & Wesson Model 637 Airweight Double Action Small Frame Revolver .38 Special 1.875" Barrel 5Rd Capacity Fixed Sights Black Rubber Grips Matte Silver Aluminum Alloy Finish

The 38 Special (38 S&W Special, 38 Colt Special) was introduced in 1902. It is essentially a slightly extended 38 Long Colt case, length 1.1551 inches, with operating pressure increased from 13,000 to 17,000 psi. Bullet diameter is .357-inch. The 38 Special became the gold standard personal defense revolver cartridge and was standard among most American law enforcement agencies for many years. Bullet weights vary from 110 to 158 grains, with a 158-grain bullet at 800 feet per second the most common. In the 1960s pressure was increased again to 18,500 psi, creating the 38 Special +P load, with increased velocity and energy. 38 Long and Short Colt ammunition can be fired in any 38 Special chamber, but not the reverse. 38 Special +P is safe in modern steel-frame 38 Special revolvers, but should not be used in aluminum-frame 38 Special revolvers. 38 Special remains a standard and popular revolver chambering. — Craig Boddington